Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755707AbbBLM2U (ORCPT ); Thu, 12 Feb 2015 07:28:20 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:36875 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755682AbbBLM2S (ORCPT ); Thu, 12 Feb 2015 07:28:18 -0500 From: Wang Nan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: , , , Subject: [RFC PATCH v2 04/26] ftrace: don't update record flags if code modification fail. Date: Thu, 12 Feb 2015 20:19:31 +0800 Message-ID: <1423743571-12180-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> References: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 63 X86 and common ftrace_replace_code() behave differently. In x86, rec->flags get updated only when (almost) all works are done. In common code, rec->flags is updated before code modification, and never get restored when code modification fails. This patch ensures rec->flags kept its original value if ftrace_replace_code() fail. A later patch will correct that function for x86. Signed-off-by: Wang Nan --- kernel/trace/ftrace.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 45e5cb1..6c6cbb1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2254,23 +2254,30 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) /* This needs to be done before we call ftrace_update_record */ ftrace_old_addr = ftrace_get_addr_curr(rec); - ret = ftrace_update_record(rec, enable); + ret = ftrace_test_record(rec, enable); switch (ret) { case FTRACE_UPDATE_IGNORE: return 0; case FTRACE_UPDATE_MAKE_CALL: - return ftrace_make_call(rec, ftrace_addr); + ret = ftrace_make_call(rec, ftrace_addr); + break; case FTRACE_UPDATE_MAKE_NOP: - return ftrace_make_nop(NULL, rec, ftrace_old_addr); + ret = ftrace_make_nop(NULL, rec, ftrace_old_addr); + break; case FTRACE_UPDATE_MODIFY_CALL: - return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); + ret = ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); + break; } - return -1; /* unknow ftrace bug */ + if (ret) + return -1; /* unknow ftrace bug */ + + ftrace_update_record(rec, enable); + return 0; } void __weak ftrace_replace_code(int enable) -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/